Railway cab signaling system for railroads



2 Sheets-Sheet l T. J. JUDGE RAILWAY CAB SIGNALING SYSTEM FOR RAILROADS Filed Jan. 25, 1935 INVENT R 15% BY ATTORNEY June I, .1937.

T. J. JUDGE June I, 1937,

RAILWAY CAB SIGNALING SYSTEM FOR RAILROADS Filed Jan. 25, 1935 2 Sheets-Sheet 2 ATTORIIEY Patented June 1, 1937 TES UiT

Thomas J. Judge, Rochester, N. Y., assignor to General Railway Signal Company,

Application January 25, 1935,

12 Claims.

This invention relates to railway signaling systerns, and more particularly to trackway apparatus and circuits for use in a railway signaling system of the type wherein signal indications are displayed in the cabs of locomotives.

In certain types of railway cabsignaling systems, the signal in the locomotive of the train is continuously conditioned in accordance with the presence or absence of energy induced in a receiving means by alternating current flowing through the rails in series of the various sections of the track. However, the Wheels and axles of the train shunt out this track circuit alternating current, so that the locomotive receiving means or coils passing over the rails must be placed in front of the first pair of wheels of the locomotive in order to be affected, and it is also necessary that the alternating current be applied to the track circuit so that the locomotive is always traveling toward the source of this current in each section. Railway systems wherein trains run in both directions: over portions of single track then present the problem of always applying the alternating current to the various track sections of the single track portions in a manner whereby the locomotive receivers can respond thereto regardless of the direction of movement of the train.

These single track railway systems are of course provided with occasional double track portions or passing sidings, and it is :desirable to permit various trains traveling in the same direction to follow each other through the portions of single track but to prevent a train from entering a single track portion while a train traveling in the opposite direction is occupying the same section.

With the above and other considerations in mind, it is proposed in accordance with the present invention to provide a railway cab signaling system, whereby the cab signal controlling energy is inductively transmitted from the trackway to the trains in accordance with trafiic conditions and regardless of the direction of movement of such trains over various sections of single track. It is also proposed to provide such a system wherein the cab signal controlling current applied to the track sections is so controlled as to permit two or more trains to follow each other at a safe distance through a portion of single track, but to prevent a train from entering a single track portion which is occupied by another train moving in the opposite direction.' It is further proposed to provide such a signaling system wherein the line circuits and apparatus are Rochester,

Serial No. 3,488

reduced to a minimum to obtain such advantages as low initial cost, low maintenance and greater reliability of operation.

Other objects, purposes and characteristic features of the present invention will appear as the description thereof progresses, during which, references will be made to the accompanying drawings, in which- Figs. 1 and 2 show in a diagrammatic and conventional manner the apparatus and circuits arranged in accordance with the present invention and constituting the trackway portion of a continuous inductive cab signaling system permitting train movements in either direction over a typical portion of single track. These two ures show adjacent portions of the railway track and are intended to be placed end to end with Fig. 2 at the right.

The straight or main track represented in the drawings is divided by insulating joints J into sections l, 2, 3, 4 and 5, the west end section I and the east end sections 5 including track switches WTS and ETS respectively, which constitute entrances into double track portions of the railway system. The west end of section I and the east end of section 5 are each connected by respective shunt wires 6 to ends of insulated portions of the track parallel therewith, so that the track sections l and 5 include the respective turn-out portions of the double track in series therewith.

Extending along the track are two wires 1 and 8 which are connected to a suitable source of alternating current energy such as generator 9 in Fig. 1, which wires '3 and 8 supply power for transmitting the signal control current from the trackway to the passing trains. Associated with the west and east ends respectively of each track section are twotransformers WF and EF (with exponents corresponding to the associated section), the primary of each of these transformers being selectively connected to the alternating current power wires 1 and 8, while the secondaries are connected directly to the rails at the respective ends of their asociated track sections.

The usual normally energized track circuit is formed in sections I and 5 by batteries B and I? which are connected in series with the secondaries of transformers WF and EF respectively to normally supply current through the portion of the associated entrance of double track, through the shunt wire 6 and through their respective portions of the main track tohold up track relays ET and WT respectively connected across the east end of section I and the west end of section 5. The conventional center-fed associated section. The batteries B B and B have suitable impedances L L and L respectively connected in series therewith in order to restrict the flow of cab signal controlling alternating current from one rail to the other at these points.

The locomotive cab signaling system intended to be employed in connection with the wayside portion of the present system has herein been shown as supplemented by wayside signals EG, EGA, WG and WGA governing train movements from the double track portions into the single track portion of the system, but no intermediate wayside signals are provided. The locomotive cab signaling apparatus forms no part of the present invention and consequently has not been shown, it being understood that the present invention embodies only the application of cab signal conditioning current to the various sections of track in a manner to inductively affect a two-indication continuous cab signaling system of the usual type which is now well known in the art. However, the general arrangement of car-carried equipment which may be used in connection with the present system is shown in Patent No. 1,730,317, granted to C. S. Bushnell onOctober 1, 1929, wherein it may be seen that the presence of alternating .current flowing in the rails of the various track sections induces current in receiver coils which is suitably amplified to hold up a control relay which energizes a green signal light, while the absence of alternating current in the rails drops the control relay and energizes the red signal light.

The present system includes a neutral line circuit having a common line wire CN whereby a west home relay WH and an east home relay EH are controlled as will be described later, and also includes a polar line circuit having a common line wire CP- whereby polar stick relays P P P and P are positioned. These polar stick relays P are of the two-position type wherein a polar armature responds to the direction of current flowing in the relay operating coil, but wherein this polar armature remains in its last operated position due to the flux from a permanent magnet after the current has been removed from its operating coil. Two directional stick relays WS and ES are controlled automatically in a manner to detect either a west bound or east bound train movement through the single track portion of the system also to be later described.

Relays WWP and EWP are the conventional polar-neutral switch-repeating relays positioned as indicated by the dotted lines in accordance with the position of the track switches WTS and ETS respectively, or in other words, the polar armature of these relays are positioned to the left or right in accordance with the normal or reverse position of the associated switch respectively, and the neutral front contact is Opened when the switch is in an intermediate position. Signal control relays EGC, EGAC, WGC and WGAC are jointly controlled by their associated WP and H relays in accordance with the usual railway signaling practice.

The neutral line circuit as Well as the polar line circuit is selectively energized from either extreme end of the single track portion shown on the drawings, and although both of these circuits are controlled at various other points a source of energy is not required in any intermediate location, the only energy source required being at each of the two ends of the single track. These sources of energy may be of any suitable nature such as a battery, the opposite terminals of which have been merely indicated herein by the symbols and Having now pointed out the essential elements of the present system, it is believed that the usefulness and the various interrelated functions of the apparatus and circuits of the present embodiment will be more readily understood by further description being given from the standpoint of operation.

The present system is illustrated in a condition wherein no trains are either occupying the single portion of track illustrated or are approaching this portion from either direction. In this condition of the system and with the polar stick contacts of relays P and P in their left hand position as shown, the neutral line circuit is energized from the right hand or east end over a circuit from polar contact In of relay P in its left hand position, neutral front contact I I of relay EWP, through the windings of relay EH front contact l2 of relay W'I front contact l3 of relay ET line wire l4, front contact l5 of relay WT, front contact [6 of relay ET line wire 17, front contact l8 of relay W'I' front contact IQ of relay ET line wire 20, front contact 2| of relay WT front contact 22 of relay ET through the windings of relay WH neutral front contact 23 of relay WWP, polar contacts 24 and 25 of relay P in their left hand position, common line wire CN, and back to through polar contact 26 of relay P in its left hand position.

Relay WH is thus held up to in turn hold up the signal control relay EGC at front contact 29 of relay WlE-I and neutral front contact 30 and polar contact 3| of relay WWP (the polar contact 3| being in its left hand position due to the normal position of track switch WTS), which In a similar manner, relay EH is held up to energize relay WGC through front contact 34 of relay EH front contact 35 and polar contact 36 of relay EWP to effect a green indication at signal WG through its front contact 31, while relay WGAC effects a red indication at signal WGA through its back contact 38. The directional stick relays WS and ES are normally energized by front contacts 40 and M respectively of their corresponding home relays WI-I and EH while stick circuits are also provided which are respectively energized by back contacts 42 and 43 of track relays ET and WT respectively.

The control circuits for the home relay EH and the directional stick relay ES have not been shown, it merely being necessary to understand that these relays correspond to relays EH and ES except that they are associated with the portion of the railway system which is adjacent the left hand or to the west of the portion shown in Fig. 1, and. are to be controlled in a similar all] manner. Likewise relays WH and WS are associated with the portion of the railway system adjacent the right hand end or to the east of that shown in Fig. 2 and are to be controlled similarly to relays WH and WS respectively.

It will now be considered that an east-bound train approaches signal EG on the main track, thereby dropping the home relay EH and the east directional stick relay ES in a manner which will be obvious from the description of the operation of relays EH and E5 The primary of transformer EF is now connected across the alternating current power wires 1 and 8 through back contact 45 of relay ES and front contact 46 of relay WS which obviously applies signal controlling current to the right hand or east end of section I, and in as much as signal EG is displaying a clear indication, the train under consideration proceeds into section I wherein this alternating current flowing in the rails effects a clear cab signal. It will be obvious that the train is now traveling toward the source of this track circuit alternating current so that the locomotive receiver coils, which are ahead of the wheels and axles, may be continually affected thereby throughout this section I.

In entering section l, the train drops the track relay ET which opens the neutral line circuit at its front contact 22, thereby dropping the home relays WI-I and EH which de-energizes all the signal control relays at both ends of the single track portion at front contacts 29 and 34 respectively and causes a red indication to be displayed by all the wayside signals in an obvious manner. It will be obvious that the red indication displayed by signals WG and WGA at the east end of the single track portion prevents a west-bound train from entering the portion of single track subsequent to the entrance of the east-bound train under consideration into section I.

The dropping of relay EH opens the energizing circuit for relay ES at front contact 4|, and this relay ES then drops in as much as its stick circuit is open at contact 43 of relay WT but however the west bound directional stick relay WS remains up due to its stick circuit completed at back contact 42 of relay ET after its normal energizing circuit is opened at front contact 40 of relay WI-I The polar line circuit is now energized from the left hand or west end over a circuit from (-1-) back contact 45 of relay E-T front contact 46 of relay WS through the windings of relay P back contact 41 of relay EGC, back contact 48 of relay EGAC, front contact 49 of relay WT, line wire 50, front contact 5| of relay ET through the windings of relay P front contact 52 of relay WT line wire 53, front contact 54 of relay ET through the windings of relay P front contact 55 of relay WT line wire 56, front contact 51 of relay ET", back contact 58 of relay WGAC, back contact 59 of relay W'GC, through windings of relay P back contacts 60 and BI of relay E8 common line wire CP, and back to through front contact 62 of relay WS In the present disclosure, it will be considered that the polar contacts of the relays P are operated in the same direction as the energizing current is stated to flow in the operating coils, so that the present energization of the polar line circuit will operate the polar contacts of all the relays P P P and P to their right hand position, or opposite to the position shown.

The primary of transformer 13F is now connected across the power wires I and 8 through polar contact 66 of relay P in its right hand position and front contact 61' of relay WT which obviously applies the cab signal controlling current to the right hand or east end of track section 2, and in a similar manner the primary of transformer EF is connected across the same power wires 1 and 8 by polar contact 68 of relay P in its right hand position and front contact 69 of relay WT to apply cab signal control current to the east end of section 3. The primary of transformer EF is connected across the power wires land 8 by polar contact ll! of relay P in its right hand position and front contact H of relay WH to supply cab signaling current to the east end of section 4, and the primary of transformer EF is also connected across the power wires 1' and 8 through back contact 12 of relay E8 and front contact 13 of relay WS to apply cab signal controlling current to the east extremity of section 5. i

It will also be obvious from the drawings that transformers WF WF WF WP and WF which are associated with the west ends of their respective sections are now all disconnected from the power wires 1 and 8. In other words, the right hand position of the contacts of the polar relays P results in the application of cab signal controlling current to the east end only of each track section of the illustrated portion of the present system, so that as the train progresses in this eastward direction, it is always moving toward the source of cab signal controlling energy in each section.

However, as soon as the train progressed eastwardly into section 2, the polar line circuit is deenergized at front contact 49 of relay WT and obviously as the polar line circuit includes front contacts of all the track relays in series. the circuit will be continuously held open while the train is traversing the single track portion. The polar contacts of all the P relays do not operate however upon de-energization of this polar line circuit, but are magnetically retained in their least operated or right hand position as previously stated.

It will be obvious that as the train clears section I to allow relay ET to pick up, relay WS is dropped as its stick circuit is open at back con- F tact 42 of relay ET picked up and its pick-up circuit is also open at contact 40 of relay WH de-energized. However, when the present eastbound train departs from section 2 into section 3 to allow track relays WT but to drop'relay WT the home relay WH is picked up over a circuit from. contact 24 of relay P in its right hand position, front contact 23 of relay WWP, through the windings of relay WH front contact 22 of relay I i-T front contact 2| of relay W'I line wire 20, front contact IQ of relay ET, backcontact I8 of relay WT polar contact 11 of relay P in its right hand position, common line wire CN, and back to through polar contact 25 of relay P in its right hand position. The picking up of relay WH then again picks up relay WS at front contact 40, and also energizes either signal controlling relay EGC or EGAC to effect a green indication at signal EG or EGA.

The relay WH is held up as the present east bound train progresses throughout the single track portion, or when the train'clears section 2, line wire 20 is connected to the common line wire CN to thereby energize relay WH over and E1 to pickup the circuit just traced, and obviously "when the train clears section 3, the line wire 20 is extended to include the line wire I1 by the closing of front contacts I 9 and I 8 of track relays ET and WT which line wire I1 is then connected to the common line wire CN at the next location to the east through front contact l6 of relay ET back contact l5 of relay WT and polar contact 18 of relay l'- in its righthand position to also maintain relay WI-I energized in an obvious manner. Finally when the train clears section 4, the neutral line circuit is extended still farther to the east to include line wire 14 which is then connected to'the common line wire CN through front contact l3 of relay ET back contact I 2 of relay WT wire 81,- and back contact 88 of relay ES, 'de-energized to thus maintain the relay WH energized while the east-bound train is occupying section 5. It will be obvious thenthat a clear indication is displayed at signal EG or EGA due to the continued energization of relay WI-I throughout the time in which the present east-bound train progressed through sections 3, 4; and 5.

In this manner it is obvious that a second eastbound train can enter the single track portion at any time after the first east-bound train has departed from section 2, and considering that a second east-bound train approaches'signal EG on the main track after the first east-bound train has departed from. section 2, this second train will drop the home relay EH and the east directional stick relayES in the same manner as described in connection with the first train. The transformer EF is then connected to the power wires 1 and 8 as before by back contact 45 of relay ES 'and front contact 46 of relay WS to thereby apply cab signal controlling energy to the right hand end ofsection I, preparatory to the eastward movement of the second train past the clear signal EG.

However it will be obvious that if the second train enters section 2 before the first train has departed from section 3, a red or danger cab signal indication will be displayed on this second train, due to the fact that the cab signal controlling energy will not be applied to section 2, in as much as transformer EF will then be disconnected from the power wires! and. 8 by the open front contact 61 of relay W'I down. It will further be obvious from the drawings that each section is arranged in this same general manner whereby the cab signal controlling current is applied to any one section only when that section and the section immediately in advance is not occupied by a train, so that when a clear or green cab signal indication is displayed, the engineer is assured that the immediate section and at least the next section is clear.

Now considering that the east bound train movements just described have been completed, or that these trains have departed from the present portion of the railway system, the neutral line circuit will again be energized as soon as the last train has departed from section 5, due to the completion of the circuit originally traced. This restores the system to normal, or to the condition in which it is illustrated, with the exception of the contacts of the P relays. which of course remain in their last operated or right hand position in as much as the polar line circuit is normally de-energized and is only energized when a train is occupying the entering sectionof the portion of single track.

- It will now be considered that a westbound CN through front contact train approaches signal WG on the main track, thereby dropping both the west home relay WI-P and the west directional stick relay WS in a manner which is analogous to the previously described dropping of relays EH and E5 in response to the east-bound train movement through the portion of the system shown in the accompanying drawings. The transformer WF will now be connected to the power wires .1 and 8 by front contact 14 of relay ES and back contact 15 of relay W8 to apply cab signal controlling energy to the left hand end of section 5 preparatory to the movement of the westbound train now under consideration past the clear signal WG, and upon entering section 5, a clear cab signal will obviously be displayed in the locomotive of the present west-bound train.

Upon entering section 5, the present west bound train de-ene'rgizes the neutral line circuit in a manner similar to the previously described east-bound train movement, or that is, the opening of front contact I 2 of track relay WT drops both east and west home relay EH and WH to obviously effect the display of a red signal indication at all the wayside signals thereby preventing an east-bound train from entering the opposite end of the single track portion. It will also be obvious that the east'direc tionalstick relay ES is held up through a stick circuit completed at back contact 43 of relay WT 'before its pick-up circuit is opened at front contact 4| of relay EH while the west directional stick relay WS is dropped due to theopening of front contact 40 of relay WH With relay ES de-energized the polar line circuit is completed as previously traced, but this time energy is applied tothe right hand or east end through back contact 8| of relay W'I and the left hand or west end is completed through back contacts 46 and 62 of relay WS The current in the polar line circuit now flows from right to left through the windings of the P relays, thereby operating their polar contacts back to their left hand position as shown in the drawings. Itwill be obvious that transformer W1 is now connected to the power wires 1 and 8 by front contact 82 of relayET and polar contact 68 of relay P in its left hand position, likewise transformer WF is connected to the same power wires 1 and 8 through front contact 83 of relay ET and polar contact 66 of relay P in its left hand. position, and finally transformer WF is connected through polar contact 64 of relay P in its left hand position and front contact 65 of relay EH to the same power wires 1 and 8.

This applies cab signal controlling current to the left hand end of each track section so that as the train progresses -in the westward direction, it is always moving toward the source of cab signal controlling energy in each section. It will also be obvious that the transformers associated with the west ends of these track sections are disconnected from the power wires 1 and 8.

When the present west-bound train departs from section 4 into section 3, the line wire I4 is connected to the common line wire CN through front contact I5 of relay W'I back contact [6 of relay ET and polar contact 18 of relay P in its left hand position to effect the picking up of relay EH in an obvious manner. The relay EH is subsequently maintained energized when the train departs fromv section 3 into section 2 by connecting line wire l1 to the common line wire I8 of relay WT back contact l9 of relay ET and polar contact 11 of relay P in its left hand position, and finally after the train departs from section 2 into section I, the line wire 20 is connected to the common line wire CN through front contact 2| of relay WT back contact 22 of relay ET wire 89 and back contact 90 of relay WS thereby maintaining relay EH energized while the present west-bound train is traversing sections 3, 2 and I.

It will of course be obvious from the previous description of following train movements in the eastward direction, that the energization of re-- lay EH by the westward train movement effects a clear indication at either signal WG or W'GA to allow a following train to enter the single track portion of the present system at any time after the first west bound train has departed from section 5. It will also be obvious that during a west-bound train movement signal controlling current is applied to any section only when that section and the section immediately in advance is not occupied by a train, in the same general manner as described in connection with eastbound train movements, so that when a clear signal indication is displayed in the locomotive, the engineer is assured that the immediate section and at least the next section in advance is clear. The system will of course be restored to normal when the present west bound train movements have been executed, or when the last train has departed from section 5, the neutral line circuit will again be energized in its entirety in the manner originally traced, thereby restoring the system to the condition illustrated in the drawings.

In systems of the present type, wherein trains traveling in the same direction are permitted to follow each other through the single track portion, the rather remote possibility of two trains traveling in opposite directions and entering opposite ends of the single track simultaneously must be considered. In other words, it will be considered that, with the present system in its illustrated condition, an east-bound train enters section I at substantially the same time that a west-bound train enters section 5. Both trains will receive a clear indication at their respective way side signals, and upon entering sections l and 5 the track relays ET and WT will be dropped, thereby maintaining both directional stick relays WS and ES energized through their stick circuits completed by contacts 42 and 43 respectively.

In this manner, it will be obvious that the energy then applied to one end of the polar line circuit will be opposed by the substantially equal potential of energy applied to the other end, which results in an insuflicient polar line circuit current to operate the contacts of the polar stick P relays from their left hand position, thereby granting superiority to the west-bound train. A red cab signal indication will then be displayed on the east-bound train upon entering section 2, inasmuch as transformer EF will be de-energized by contact 66, while the west-bound train will receive a green cab signal indication until entering section 3, whereupon a red indication will be displayed by the de-energization of transformer WF at open front contact 83 of relay ET de-energized by the east-bound train.

Of course one train approaches the single track portion of the present system in nearly every instance sufiiciently in advance of any other train traveling in the opposite direction to establish the directional selecting means and hold the later train to the rear of its governing wayside signal, but it will be seen from the above that even in the remotely possible instance of substantially simultaneous entrances from opposite ends, the twotrains will be stopped even before entering the same track section.

I A signaling system for single track railways has thus been provided, wherein alternating current is selectively superimposed on direct current track circuits in accordance with forward traffic conditions, whereby to efiect the display of a clear or a danger signal indication in the cabs of passing locomotives, and wherein such superimposed current is also selectively applied to one end or the other end of each section according to the direction of movement of the train, this being arranged in a manner to permit continuous inductive reception of signal controlling energy on the locomotive throughout each section. The above has been accomplished by simple and reliable means including a neutral line circuit and a polar line circuit, the neutral line circuit being employed to selectively de-energize one of two normally energized stick relays in accordance with the direction of traffic, which selection in turn selects the direction of current in a momentary energization of the polar line circuit to distinctively position various magnetic stick relays and. establish a condition of the system associated with either traffic direction.

Another important feature of the present invention is the utilization of the neutral line circuit to efiect the control of wayside signals governing the entrance of trains into the single track portion of the railway system in accordance with the direction of movement of a train occupying this portion as established by a momentary energization of the polar line circuit. The control of the wayside signals thus provided is efiective to prevent a train traveling in the opposite direction from entering this single track portion and yet to permit trains, spaced by a safe distance, to following each other through the portion of single track. This feature is also effected in a very'simple and reliable manner by successively completing portions of the neutral line circuit which is in the rear of the traversing train only, the rear direction being determined by the established position of contacts of the various magnetic stick relays, thus allowing the wayside signals in the rear of the train to display a clear indication after the train has moved a safe distance in advance thereof, but retaining a danger indication at the wayside signal governing opposing train movements into the single track.

The above rather specific description of one form of the present invention is given solely by the way of example, and is not intended, in any manner whatsoever, in .a limiting sense. It is also to be understood that various modifications, adaptations and alterations may be applied to meet the requirements of practice, without in any manner departing from the spirit or scope of the present invention, except as limited by the appended claims.

What I claim is:--

1. In a signaling system for railroads having a portion of single track connecting two portions of double track, the combination of wayside signals governing the entrance of trains into the ends of the single track portion, a neutral line circuit controlled in accordance with the. occupancy of various sections of the single track, means controlling the wayside signals in accordance with the energization of the neutral line circuit, a polar line circuit energized by the enresponsive means selecting the direction of current in the polar line circuit in accordance with the direction of movement of said train, magnetic stick relays positioned in accordance with the direction of current in the polar line circuit, means selectively applying alternating current energy to one end or the other end of each track section in accordance with the position of the magnetic stick relays, means controlling the application of said alternating current in accordance with traiiic conditions, and means for energizing one end portion or the other end portion only of the neutral line circuit in accordance with the position of the magnetic stick relays.

2. In a signaling system for railroads having a portion of single track with adjacent portions of double track, a neutral line circuit controlled in accordance with trafiic conditions in the single track, wayside signals at the entrances to the single track governed in accordance with the energization of the neutral line circuit, polarstick relays controlling the application of cabsignaling energy to various sections of the single track, means positioning the polar-stick relays in accordance with trafiic direction, and means controlled by the polar-stick relays for permitting energization of the portion of the neutral line circuit in the rear only of a train traversing the single track.

3. In a signaling system for railroads having a portion of single track with adjacent portions of double track, a neutral line circuit controlled in accordance with trafiic conditions in the single track, wayside signals at the entrances to the single track governed in accordance with the energization of the neutral line circuit, polar-stick relays controlling the application of cab-signaling energy to various sections of the single track, means positioning the polar-stick relays in accordance with trafiic direction, and means controlling the neutral line circuit in accordance with the position of the polar stick relays Whereby to permit following train movements through the single track.

4. In a single track railway signaling system, a polar line circuit, a neutral line circuit, wayside signals controlled by the neutral line circuit and governing the entrance of trains into the single track, relay means positioned according to the direction of current in the polar line circuit and arranged to retain such position after de-energization of the polar line circuit, means energizing the polar line circuit upon entrance of a train into a first portion of the single track with a direction of current corresponding to the c direction of movement of the train, means preventing further energization of the polar line circuit while said train occupies the remaining portion of the single track, means applying alternating current to one end or the other end of various sections of the single track according to the position of the relay means and in accordance with trafiic conditions, and means affecting one end or the other end of the neutral line circuit according to the position of the relay means in a manner to permit following train movements through the single track.

5. In a single track railway signaling system, wayside signals governing the entrance of trains into each end of the single track, means including a, first line circuit for causing the display 10f a restricted indication at the wayside signals at one end while a train entering the other end is occupying the single track, a second line'cirtrance of a train into the single track, directional cuit controlling magnetic stick relays in accordance with the direction of current therein, means ,for transiently energizing the second line circuit upon the entrance of a train into the single track with a direction of current corresponding to the direction of movement of the train, and means controlling the first line circuit in accordance with the position of the magnetic stick relays and trafiic conditions whereby to cause the display of a proceed indication at a wayside signal after a train has progressed a predetermined distance in advance thereof.

6. In a single track railway signaling system, a plurality of insulated track sections, a. line circuit extending along the single track, means transiently energizing the line circuit with one direction of current upon the entrance of a train into one end of the single track and with another direction of current upon the entrance of a train into the other end, magnetic stick relays positioned in accordance with the direction of current in the line circuit, and means for applying alternating current energy to one end or the other end of each track section according to the position of the magnetic stick relays.

7. In a single track railway signaling system, a plurality of insulated track sections, a line circuit extending along the single track, means energizing the line circuit with one direction of current during the occupancy by a train of one end of the single track and with another direction of current during the-occupancy by a train of the other end, magnetic stick relays positioned in accordance with the direction of current in the line circuit, means for applying alternating current energy to one end or the other end of each track section according to the position of the magnetic stick relays, and means preventing said application of alternating current energy to an end of any track section when the track section adjacent such end is occupied by a train.

8. In a single track railway signaling system, a plurality of insulated track sections, a line circuit extending along the single track, means temporarily energizing the line circuit with one direction of current upon the entrance of a train into one end of the single track and with another direction of current upon the entrance of a train into the other end, means preventing further energization of the line circuit while a train occupies the single track, magnetic stick relays positioned in accordance with the direction of current in the line circuit, means for applying alternating current energy to one end governing the entrance of trains into the single track to prevent a train from entering the single track when occupied by another train moving in the opposite direction, means including directional responsive relays for permitting a train to enter the single trackafter another train moving in the same direction has progressed a predetermined distance into the single track, and means including contacts of stick relays controlled by the directional responsive relays for applying cab signal controlling energy to the exit end of sections of the single track only when at least one section adjacent such exit end thereof is unoccupied by a train.

10. In a signaling system for railroads having a portion of single track with adjacent portions of double track, a neutral line circuit controlled in accordance with traffic conditions in the single track, wayside signals at the entrances to the single track governed in accordance with the energization of the neutral line circuit, polar relays controlling the application of cab-signaling energy to various sections of the single track, means positioning the polar relays in accordance with traffic direction, and means controlling the neutral line circuit in accordance with the position of the polar relays whereby to permit following train movements through the single track.

11. In a single track railway signaling system, a plurality of insulated track sections, a line circuit extending along the single track, means temporarily energizing the line circuit with one direction of current upon the entrance of a train into one end of the single track and with another direction of current upon the entrance of a train into the other end, means preventing further energization of the line circuit while a train occupies the single track, magnetic stick relays positioned in accordance with the direction of current in the line circuit, means for applying alternating current energy to one end or the other end of eachtrack section according to the position of the magnetic stick relays, and means preventing said application of alternating current energy to an end of any track section when the track section adjacent such end is occupied by a train, a signal at each of the ends of the single track, means putting both signals to stop upon the entrance of a train into the single track, and means depending upon said line circuit for putting the signal at the entering end of the track to clear upon the train proceeding a predetermined distance along the track.

12. In a signaling system for railroads having a portion of single track divided into insulated track sections; polar-responsive stick relays, automatic traflic-responsive means for establishing a position of the stick relays in accordance with the direction of traffic, means applying alternating current energy to one end or the other end of each track section according to the established position of the stick relays, and means permitting entrance into one end or into the other end of the portion of single track when occupied by a train in accordance with the established position of the stick relays.

THOMAS J. JUDGE. 

